Expansion valve



Feb; 24, 1942. A. F. (.ZARROLL 2,274,127

I EXPANSION VALVE Filed Feb. 16, 1939 5; F2 :1 m J m /a a Z 9 J a? 3L 1 INVENTOR.

ATTORNEY.

Patented Feb. 24,

EXPANSION vatva Arthur F. Carroll, Milwaukee, Wis., assignor to I Automatic Products Company, Milwaukee, Wis., a corporation of Wisconsin 1 Application February 16, 1939, Serial No. 256,644

4 Claims.

This invention relates to'an improvement in expansion valves for use with refrigerators and designed to feed the refrigerant into. the evaporator in correct proportions to maintain maximum evaporator eiliciency without frost-back to the compressor unit and also to prevent the flow of refrigerant during the off period.

One of the principal objects of the invention is to simplify and compact the construction of the valve possessed of these advantages and capacities and this in such a way as to assure its efflciency under conditions of actual use and yet make it practical to produce the valve economically and by means of facilities and from materials ordinarily available.

A further and more specific object of the in vention is to improve the mounting and action of the valve so as to make it self-alining, render it capable of maintaining a constant evaporator pressure and assure its eflicient and normal action even though the valve casing be subjected to such rough usage as to be slightly distorted.

A still further object of the invention is to provide a device of this character and having the advantages mentioned and wherein fine accurate adjustment is provided for permitting accurate adjustment of the valve to the system.

Another object of the invention is to provide a valve of this character which may be used with either sulphur dioxide, Freon or methylchloride and has an adjustable range from 20" vacuum to 30 lbs. pressure. 1

other objects and advantages reside in certain novel features of the construction. arrangement and combination of parts which will be hereinafter more fully described and particularly pointed out in the appended claims, reference being had to the accompanying drawing forming a part of this specification, and in which:

Figure 1 is a view in diametrical vertical cross section showing an automatic expansion valve embodying the present invention, parts being shown in elevation for the sake of illustration;

. for connection to the liquid feed and an outlet fitting 8 adapted for connection to the evaporator (not shown). inlet fitting to a ported partition Ill which is interposed between the inlet passage 9 and the outlet. A cylindrical valve guide II is provided with a reduced and externally threaded extension [2 which'is threadedly interconnected with An inlet passage 9 leads from the valve.

the inner peripheral wall of the ported partition. The reduced extension I! of this guide is provided with a valve seat I! which is press fitted and soldered in place. A needle valve ll coacts with the valve seat l3 and is carried and suitably secured in a valve holder I5. The valve holder I5 is floatably mounted in a cup-shaped piston or guide l6 which has a cylindrical body portion telescoping or slidably fitting over the valve guide II. The end wall ll of the guide I6 is provided with an opening at its center through which a reduced extension l8 of the valve holder l5 extends. The extension i8 has .a head. I9 at its lower end and a spring 20 is interposed between the head l9 and the lower face of the end wall ll of the guide IE to provide a floating or selfcentering mounting for the valve holder and The open end of the valve guide It is provided with an outwardly extending annular flange 2|. Passages It provided in the fixed valve guide provide for free fiow of the liquid 7 from the interior of the guide to the outlet side of the valve.

A coil spring 25 encircles the guide l6 and atone end abuts its flange 2i and at its other end engages an adjustable abutment 26. The abutment .26 is provided with a conical bearing portion 21 engaging a correspondingly formed seat in the plug 28 which is threadedand soldered to an-end cap 29 threadedly interconnected with the lower end of the valve body and also soldered thereto. The cap 29 and its plug 28 are factory set so that the compression of the spring 25 is accurately predetermined.

A diaphragm 30 is clamped between the upper end of the valve'body and a head or bonnet 31. The periphery of the head or bonnet 3| is formed around the periphery of the valve body as indicated at 3| so as to be mechanically connected and hermetically sealed to the valve body and to the peripheral portion of the diaphragm 3ll The underside of the diaphragm is provided with a pad 32 which is engaged with the upper ends of push pins 33 slidably interfitted in openings in the valve body and engaged at their lower ends with the flange 2| of the valve guide. Preferably three such push pins 33 are provided, as illustrated in Figure 2. The diaphragm is loaded by means of a spring 35, the lower end of which rests in a spring seat 36 flatly engaged with the diaphragm and the upper end of which is engaged by a spring seat 31 controlled as to position by means of an adjustable cap 38 equipped with a knob 39 to facilitate its manipulation. The cap 38 has its cylindrical body portion externally threaded and threadedly engaged with the internal threads of an upstanding cylindrical extension of the head or bonnet 3!. To adjust the 4 valve all that need be done is to turn the knob 39 by turn, allowing sumcient time between body itself be distorted, the guiding not be impaired.

against air or moisture and prevent freeze-up of r the head.

There is suficient clearance between the outer surfaces of the push pins and the walls of the openings in which they slide to permit the pressure on the outlet side of the valve to act on the underside of the diaphragm.

As indicated, the inlet l of the valve is connected to the liquid feed line of the refrigerating system and the outlet 8 is connected to the evaporator thereof. Hence the evaporator pressure is exerted on the underside of the diaphragm and tends totlex it upwardly, allowing the needle valve M to close under the influence of its spring 25. In this position of course, no refrigerant flows. When the evaporator temperature has become warm enough to close the contact in the control switch of the refrigerator, the compressor thereof starts, which has the effect of lowering the pressure in the evaporator. When the pressure drops to the lower operating point predetermined by the adjustment of the valve, the diaphragm 30 flexes downwardly under the influence of spring 35. Such downward flexure of the diaphragm acts through its pad 32, through the push pins 33 and piston or guide if to pull the needle valve downwardly away from its seat, the action of the spring 25 being overcome. This allows the refrigerant to flow past the valve seat 13, through the openings Hi, to the outlet 8 and thus to the evaporator. The pressure increase caused by the boiling of the liquid admitted to the evaporator tends to re-close the needle valve, while any reduction of evaporator pressure tends to cause the needle valve to open. During operation, at any valve opening, the evaporator pressure just counterbalances the spring 85 and the diaphragm is balanced. Any slightest change in pressure will tend to increase or decrease the needle valve opening thereby maintaining a con stant evaporator pressure. When the compressor stops, the increased pressure closes the needle the valve housing and completely housed and protected, so much so that even though the valve action will inwardly from the periphery thereof, said chamber having an inlet opening, a valve seat in said opening, a hollow sleeve extending adiacently from. said seat, outlet passages in said sleeve adjacent said seat, a cup-shaped member fitting over and around said sleeve, a valve carried by the bottom of said cup-shaped member and extending upwardly within and spaced from said sleeve and adapted to engage said valve seat, a spring abutment on the upper edge of said cupshaped member, a plug for said recessed chamber having a spring abutment fitting within said chamber, and a spring positioned in said chamber and acting between said abutments.

2. In a diaphragm controlled expansion valve, a casing having a recessed chamber extending inwardly from the periphery thereof, said chamber having an inlet opening, a valve seat in said opening, a hollow sleeve extending adjacent-iv from said seat, outlet passages in said sleeve adjacent said seat, a cup-shaped member fitting over and around said sleeve, a valve carried by the bottom of said cup-shaped member and extending upwardly within and spaced from said sleeve and adapted to engage said valve seat, a spring abutment on the upper edge of said cupshaped member, a plug for said recessed chamber having a spring abutment fitting within said chamber, and a spring encircling said cup-shaped member and acting between said abutments.

3. In a diaphragm controlled expansion valve. a casing having a recessed chamber extending inwardly from the periphery thereof, said chamber having an inlet opening, a valve seat in said opening, a hollow sleeve extending adjacently from said seat, outlet passages in said sleeve adjacent said seat, a cup-shaped member fitting over and around said sleeve, a needle valve floatably carried by the bottom of said cup-shaped member and extending upwardly within and spaced from said sleeve and adapted to engage said valve seat, a spring abutment on the upper edge of said cup-shaped member, a plug for said recessed chamber having a spring abutment fitting within said chamber, and a spring positioned in said chamber and acting between said abutments.

4. In a diaphragm-controlled expansion valve, a casing having a recessed chamber extending inwardly from the periphery thereof, an inlet opening in the top of said chamber, an outlet opening in the side of said chamber, a cylindrical valve guide spaced from the walls of said chamber-and extending downwardly from said inlet opening, a valve seat at the top of and within said guide, an aperture in the wall of said guide adjacent said seat providing a passageway from said inlet opening to said chamber and said outlet opening, a valve-holding member having a cylindrical portion telescoping over and slidably guided by the outer surface of said valve guide, a valve carried on the bottom of said valveholding member and projecting upwardly within said valve guide to engage with said seat and spaced from the walls of said guide, a spring abutment on the upper edge of said valve-holding member, a plug for said recessed chamber, and a spring acting between said abutment and said plus.

ARTHUR F. CARROLL. 

